Honestly, it's probably not because of her approach (unless she's running from him). More likely is that he's just getting bolder. Human aggressive Cockerels/Roosters target kids first and then smaller women and will eventually try for the full grown man. If he's showing signs of being aggressive, he may just get worse. He's going through puberty right now and that's typically when the aggression starts.
Everyone here will have different advice. Most will tell you to get rid of him because there are plenty of good roosters out there. Some will tell you to pick him up and give him treats. I'm not a fan of this method because 1) that gets him closer to your face where he can inflict more damage and 2) it's rewarding bad behavior.
I have an 8 month old cockerel that flogged me once. I'm a small woman. I calmly walked towards him and used this method:
This was a few weeks ago and he hasn't shown me aggression since BUT I will say it will not work on every cockerel and I'm not even sure if this is a permanent solution. I'm fully prepared to dispatch him if aggression continues. Every one is an individual so what may work for one chicken, won't for another.